1. Field of the Invention
The present invention relates to a stage apparatus, an exposure apparatus, and a method of manufacturing a device.
2. Description of the Related Art
In recent years, to improve the productivity of a semiconductor manufacturing apparatus, an exposure apparatus which includes two substrate stages and performs a process for exposing a substrate and a process for aligning a substrate in parallel is available. Such an exposure apparatus using two substrate stages can improve its overall processing speed as compared with a conventional scheme of performing a process for exposing a substrate and a process for aligning a substrate in series.
FIG. 7 is a plan view showing a stage apparatus 100′ including two substrate stages 20′ and 30′. In an exposure station shown on the left side of FIG. 7, a projection optical system (not shown) performs a substrate exposure process. Also, in an alignment station shown on the right side of FIG. 7, an alignment optical system (not shown) performs a substrate alignment process. The stage apparatus 100′ shown in FIG. 7 performs an exposure process on the substrate stage 20′ and an alignment process on the substrate stage 30′ in parallel. After both of these processes are completed, the substrate stages 20′ and 30′ are swapped. The substrate stage 30′ having undergone a substrate alignment process moves to the exposure station, and undergoes a substrate exposure process in the exposure station. The substrate stage 20′ having undergone a substrate exposure process moves to the alignment station. In the alignment station, a substrate transport system (not shown) recovers the processed substrate from and provides a new substrate onto the substrate stage 20′, and the substrate stage 20′ undergoes an alignment process of the newly provided substrate. A substrate exposure process is continuously performed by repeating this sequence.
The stage apparatus 100′ includes movable bodies 22′ and 32′ provided in one-to-one correspondence with the two substrate stages 20′ and 30′. The movable bodies 22′ and 32′ respectively hold and relay pipe lines 21′ and 31′ which supply fluids such as coolants and gases for static pressure bearings to the substrate stages 20′ and 30′, or wiring lines 21′ and 31′ which supply, for example, currents such as electrical signals and powers to the substrate stages 20′ and 30′. If the movable bodies 22′ and 32′ are immovably fixed in position, the pipe or wiring lines 21′ and 31′ need to have lengths long enough to allow the substrate stages 20′ and 30′ to be driven over driving ranges necessary in exposure and alignment. In this case, depending on the positional relationship between the substrate stages 20′ and 30′, the lines 21′ and 31′ may interfere with their unconnected substrate stages 20′ and 30′ or other constituent members of the stage apparatus 100′ inside/outside the substrate stages 20′ and 30′. In addition, the lines 21′ and 31′ must be as short as possible in order to suppress any vibration and reaction forces.
To surmount these difficulties, Japanese Patent Laid-Open No. 2006-287122 describes a technique of providing the stage apparatus 100′ with a driving mechanism which drives the movable bodies 22′ and 32′, and moving the movable bodies 22′ and 32′ in synch with the substrate stages 20′ and 30′ during an alignment process and exposure process. Japanese Patent Laid-Open No. 2006-287122 detects the relative position between the movable body and the substrate stage, and controls driving of the movable body so that the detected relative position stays constant.
However, an alignment process and an exposure process generally require driving the substrate stage with high accuracy on the order of nanometers and high speed under high-response control. For this reason, to drive the movable body in synch with the substrate stage, they need to be controlled in synch with each other in real time with high accuracy on the order of nanometers and high speed, leading to complication of the control. The movable body also requires a driving mechanism and control mechanism which can attain a speed and accuracy as high as those for driving the substrate stage, resulting in increased cost. As the control response in driving the movable body increases, vibration of the movable body, in turn, increases. This may cause disturbances to the substrate stage through objects, which are prone to transmit vibration, such as the pipe and wiring lines and the floor.